The Grundrisse
In the Grundrisse, Marx explains how the commodity form contains in-itself all the elements necessary for advanced capitalist crisis: namely, 1) the separation of exchange into acts removed in time and space; 2) the possibility, in this gap, of reversing C-M-C (exchange) into M-C-M (capital accumulation), and 3) the parallax between the "fleeting moment" of money in C-M-C and its "hard form" as wealth, as the universal commodity (and not just the universal equivalent, as in exchange).And certainly one can unfold everything from this simple to the complex (capitalist crisis) in this way. This, by the way, is the Grundrisse en résumé.
Capital
Das Kapital works rather differently. It's extremely important to coordinate the "real" from the conceptual, and one might say that the book alternates between these two.For instance: the chapter on the working day. Obviously the working day itself could have been the starting point for an analysis of capitalism's exploitative nature, as in Engels' study of British labor conditions. But in Das Kapital, the immediate, really existing working day only follows from the (concept of) rate of surplus-value.
And this is true all along the line. Wages, which we all can point to in real life, follow from the (concept of) value of labor-power. Prices, which are by no means a rare phenomenon, follow from (the concept of) exchange-value.
The most important of these determinations is that of profit (in the bookkeeping sense) by surplus-value. So, for Marx, conceptual determinations have ontological priority over their reflected appearances--but at the same time, unlike Hegel (!), Marx always stresses that history is not *itself* the unfolding of these determinations; and, in turn, these abstractions are not intuited from nowhere (as "eternal laws") but are themselves arrived at from an analysis of real processes.
[As Lukács writes: On one hand, it is impossible to consider social being ontologically without beginning from the most basic facts of man's daily life... On the other hand, reality presents itself in a quite deformed character... It is necessary to start from quotidian life, but also to overcome it..."]
So, just as profit from the capitalist's perspective *precedes* the larger-scale "departments" of the reproduction of the aggregate social capital, CONCEPTUALLY it is the reverse: it is necessary to show how all of social capital turns over (volume 2) in order to establish the real existence of profit determined by the "average rate of profit" (volume 3). (And that is those volumes en résumé).
And I think this is why Das Kapital begins the way it does, with the commodity form: it is in the object of labor that value (the primordial concept) makes its first appearance, and in bourgeois society this object of labor is ONLY a commodity, QED.
